We currently have two questions that are essentially asking for protocol comparisons. One is already closed and fails to garner reopen votes even after a edits, the other stands at three close votes.

Difference Between ZigBee and Z-Wave?

When to use Wi-Fi over Bluetooth or vice versa in an IoT system?

I want to get meta involved about the comparisons of the like and what I'd suggest should be a requirement for these questions to be on-topic.1

When protocol comparisons should off-topic

Both questions are in their first revisions way too broad since they do not contain any information about the goal of the IoT application the asker has in mind (Q1Rev1, Q2Rev1). Essentially the question is each time here are two protocols, which is better?

Those questions should be off-topic for two reasons:

  • It asks for a complete pro-con analysis on all areas of the protocol. That's too broad.
  • There is no real association to IoT

When protocol comparisons should be on-topic

  • A clear goal of the IoT system is stated
  • Clear requirements for the network level can be stated

Let's discuss our ideas and opinions which criteria should be added to which list or which criteria you disagree with.

1: Disclaimer: I voted to close both and refused a reopen vote to the first after an edit in the review queue. I retracted my close vote on the second after the edit.

2 Answers 2


Where the question is essentially "list all the similarities/differences between the protocols", I would say that it is too broad/off-topic, because those questions simply don't work well with the Stack Exchange format. The stance from Robert Cartaino is that these are too broad, so I think it's best to go with that rather than off-topic (which, on reflection, is rather backwards that a post about IoT protocols is off-topic, but I just considered it an oddity of SE).

I also agree completely that questions that do specify requirements can be valid questions on IoT. For example, "In an area with significant Wi-Fi interference, which protocol would be most appropriate to connect _____ to an IoT network?" could be a good question idea, because the constraints are clear.

In essence:

  • if you could answer the question with a table comparing protocols, it's not a good question (too broad)

  • if answers can't actually tell you which protocol would be best, it's not a good question (too broad/unclear)

  • if answers can sum up the pros and cons for a situation and give you an answer as to which is best, the question is on-topic.

  • 3
    Questions about protocols are not off topic, but general comparisons Don't work well with the SE format is the essence of why they are "too broad". Don't call everything that doesn't work here "off topic" as a catch-all way to close posts. It only confuses the dickens out of just about everyone else not privy to these meta discussions. Dec 7, 2016 at 21:23
  • @RobertCartaino thanks for the clarification, I'll edit my posts to reflect that now since I wasn't really sure whether SE did consider those off-topic in some cases.
    – Aurora0001
    Dec 7, 2016 at 21:25
  • 1
    On/off topic can be a moving target within the community, and it certainly seems to defy any form of reason that questions about Z-Wave or Zigbee protocols would be off-topic on an IoT forum. "Too broad" is another beast entirely and I think you are very correct in observing that's more the issue here -- in which case whether or not it is about protocols seems besides the point. "Primarily opinion based" applies to the wifi vs. bluetooth thing, regardless of how it is qualified...which again means the topic of protocols is mostly besides the point.
    – goldilocks
    Dec 7, 2016 at 22:49

I don't think the issue with those questions, both of which I voted to close, really has anything to do with the fact that they involve comparing protocols, except to the extent that questions about comparing __________ tend to be one or both of:

  • Too broad, if a question implicitly demands a summary explanation of the protocols. Which if it doesn't, the question probably would not be that general to start with. Asking "(How) can I accomplish ______ with protocol X?" or "Does protocol X support _______ like protocol Y?" are fine.

  • Primarily opinion oriented. Some people are going to insist you should only use UDP unless there is a good reason not to use TCP and vice versa, but these are personal opinions and preferences. This is python vs. ruby, emacs vs. vim, Apple vs. Android, the Red Sox vs. the Yankees, etc. It has a place, but the place is not a Stack Exchange site.

So I don't see any need to lay down special rules regarding the topicality of protocols. If asking a question about zigbee or z-wave or bluetooth, or wifi in an IoT context, is off topic, then "Internet of Things" might as well be off-topic.

It is also worth noting that just because a question may be appropriate to another SE site -- perhaps even, more appropriate -- does not by definition mean it must be off-topic here. There is at this point plenty of topical cross-over between SE sites and while I am aware many people objected to this evolution, it's pointless to keep harping about it.

Put another way, topicality should largely ignore the existence of other S.E. sites. IoT by nature must involve networking protocols, so there is little reason any questions about them in that context be singled out as off-topic.

Again, that doesn't mean that anything involving a protocol cannot be closed for other reasons, or that every question about bluetooth must be on-topic.

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